Heating and cooling apparatus



'March 29, 1949. N, MORRIS l2,465,389

HEATING AND COOLING APPARATUS 4 sheets-sheet 1 riginal Filed April 2e,1944 AELS-n2.

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HEATING AND C OLING APPARATUS A Original Filed April 26, 1944 v 4Sheets-Sheet 4 i /O VOLT Qzmaw a 91mm) 'M www Patented Mar. 29, 1949HEATING AND COOLING APPARATUS Nathan Morris, Silver Spring, Md.,assignor, by mesne assignments, to American Instrument Co., Inc., acorporation of Maryland Original application April 26, 1944, Serial No.532,807. Divided and this application August 3, 1945, Serial No. 608,623

7 Claims.

My invention relates broadly to heating and cooling apparatus and moreparticularly to the system and apparatus for producing accuratelycontrolled temperatures.

This application is a division of my application Serial Number 532,807filed April 26, 1944 for Refrigeration apparatus.

One of the objects of my invention is to provide a method of controllingextremely low temperatures in a refrigeration cabinet with a high degreeof precision.

Another object of my invention is to provide a construction of apparatusfor producing and maintaining relatively low temperatures in a cabinetutilizing solidified gas as the refrigerant.

Still another object of my invention is to provide a refrigerationapparatus having a solidified gas refrigeration cabinet with acirculator therein for cyclically pumping low temperature gas through awork chamber.

A further object of my invention is to provide a novel control systemfor refrigeration apparatus whereby heat or fluid circulation may beintermittently controlled for maintaining the temperature within arefrigeration cabinet substantially constant.

A further object of my invenion is to provide a system of dual fanoperation for low temperature refrigeration cabinets with means forcooperatively controlling the operation of the fans whereby one of thefans may be constantly driven for maintaining circulation of therefrigerating gas within the cabinet while the other of the fans isintermittently driven according to the temperature requirements for theparticular Work being performed within the cabinet.

Other and further objects of my invention reside in the method ofoperation and control arrangement set forth in the specificationhereinafter following by reference to the accompanying drawings inwhich:

Figure 1 is a plan view of one construction of refrigeration apparatusembodying my invention; Fig. 2 is a vertical sectional View taken online 2-2 of Fig. l; Fig. 2a is a detailed view showing one arrangementof sealing the entrance way for the shaft which connects one of theexternal driving motors to one of the gas circulating fans in thecabinet structure; Fig. 3 is a horizontal sectional view through thecabinet structure taken substantially on line 3-3 of Fig. 2; Fig. 4 is atransverse vertical sectional view taken through the cabinet structuresubstantially on line 4-4 of Fig. 3; Fig. 5 is a vertical sectional viewthrough the cabinet structure taken substantially on line 5-5 of Fig. 6;Fig. 6 is a plan view similar to the plan view of Fig. 1, butillustrating one section of the hinged top of the cabinet opened to showthe interior of the dry ice compartment; and Fig. 'I is a wiring diagramillustrating the electrical circuit arrangement for the control unitsemployed in the refrigeration system of my invention.

Referring to the drawings in more detail reference character Idesignates the refrigeration cabinet embodying my invention and in whichlaminated insulation material having high heat insulation propertiesconstitutes the wall structure of approximately six inches in thickness.The insulation material is covered externally by suitable heatinsulation surfacing material such as laminated board represened at 2.The interior of the cabinet is provided with a metallic liningrepresented at 3 which has all joints well lled and caulked to eliminateinsofar as is practicable the loss of refrigeration by heat transferthrou-gh the walls of the cabinet. A cover formed in sectionsrepresented at 4 and 5 hinged together as represented at 6 extends overthe cabinet structure and is secured in tight sealed relation thereto byhasps 1 which when forced into securing position insure a gas-tightjoint between the metallic peripheral extension 8 of the lining 3 andthe metallic facing 9 and ID of the cover section s d and 5. The coversections 4 and 5 are constructed in a manner similar to the constructionof the main cabinet in that the internal laminated heat insulation isfaced on its lower surface by metallic material 9 and l0 and covered onthe peripheral edges and upper surface by laminated wood or otherinsulation material indicated at ll.

The interior of the cabinet is divided into a work chamber representedat i4 and a Dry Ice compartment represented at i5 by means of apartition I6 of insulation material. The par"i tion I6 extendstransversely of the interior of the cabinet termination above the bottomof the cabinet at I1. The partition is formed from lavninated insulationmaterial enclosed by metallic sheet-like material represented at I8, onesurface of which forms the transverse Wall of the work compartment i4and the opposite surface of which I9 constitutes one Wall of the Dry Icecomrartment which terminates at the level l1 is arranged to receive abasket or box-like carrier represented at 20 that is provided with anopenwork mesh-like side 2| at one end thereof for the free circulationof gases under control of the blower represented generally at 22.

The blower includes mounting means which is suitably secured through theinterior side wall of the cabinet. Drive shaft 21 is connected to motor28 supported externally of the cabinet on suitable mounting bracket 29.A sealing gland is provided 'between motor .28 :and the rexternal sidewall of the cabinet as represented at 39 for preventing loss ofrefrigeration. The sealing gland comprises a substantially resilientgasket which is compressed between the end ofthe motor frame 28 and theside wall of the cabinet for substantially preventing heat exchangethrough .the tubular member 26.

The intake for gases is established through the center aperture 40 ofthe .housing which is in close proximity with the openmesh side wall 2|of the Dry Ice container 20. The delivery end of the fan 35 is connectedto the duct system 4| which, when the fan housing is properly mounted inposition, extends vertically in the Dry Ice compar'tment and forms aslip connection coupling means with the depending end 42 of the elbow 43o'f horizontally extending duct 44. yThe horizontally extending duct 44is constructed internally for reducing friction to gas ow through theduct system. The end of the horizontally extending duct 44 projectsthrough a recess 44a formed in the partition I6 and projects into theupperportion of the work compartment I4. The endV of the duct 44 isprovided with a transversely extending frame member 41 which tsthereon-an'dfserves as a guide for an adjustable plate member 48 whichmay be adjusted between setsof coacting guide grooves indicated at 49and 50. The adjustable plate 48 has a projecting finger grip portion 5|enabling the plate to be manually grasped and moved to selectedpositions to `fully open or partially close aperture 52 in plate 41'forthus controlling the volume of gas 'ilowfrom the'refrigerationcompartment into the work compartment. In order to confine the forcedgas flow into the work Acompartment from the refrigeration compartmentto the ductsystem I provide a de- 'iiectoriplate 53 which extends fromthe top of the guide` plate' frame 41 to a position establishing sealed'relation with the entire surface of the jcover section 4. Asrepresentedin Fig. 4 the deector plate V53 extends only partially acrossthe cabinet forcing the gases to pass throughthe .conned space indicatedat 46 so that' the return gases are'free to pass through the elongatedslot or recess indicated at 46 in their convection path `fr0m the workcompartment into the refrigeration compartment.

AIn addition to the blower 22 which I have described-I also provide anarrangement of fan 55 which is mounted below the refrigerationcompartment centrally of'the interior of the cabinet lon shaft56 whichextendsthrough the tubular member .51.in the side wall of the cabinet tothe `motor 58 supported on Vbracket 59 on the exterior of the cabinet. Acompressible gasket 60 is compressedbetween the end of tubular sleeve51-and motor housing y58 for providing a. gas-tight seal `and preventingheat exchange between the ex- '.terlor atmosphere and the interior ofthe cabinet.

An annular ring member 6| is secured against the gasket 60 forcing thegasket 6D into tight sealing .relation with the end of the.motorhousing. An

"annular rim member 62 iits over the ring 6| and 'gasket 6|);as shown.The vfan 55 is located beneath the refrigeration compartment and in line`with the heaters 63 that `aresupported on frame 64 that extendstransversely -`of'the cabinet imarrangement of the wire coils 63a and63D which comprise the heaters 63. A series circuit may be completedthrough the wire coils 63a and 63h by moving 'switcharms '65a and 65o tocontacts 66o and 65d, respectively. Either section of the lheater may beutilized separately by moving switch arms 65a and 65o to contacts 65eand 65d; or to contacts 65o and 65e, respectively. A parallelvarrangement of the wire coils 63a and 63h may be effected by movingswitch arm 65h to contact with both contacts 65j and 65g which are wiredas shown at the same time that switch arm 65a is moved to contact 65e.Various arrangements of series parallel systems may be employed forcompleting the circuit connections to the wire coils 63a. and 63h. Theconnection of the heaters into vthe power supply circuit 66 iscontrolled by mercury switch 61 actuated by armature t8 controlled bysolenoid winding 69 which is energized or de-energized in accordancewith the position of the thermostat 10 the control element of whichextends into the cabinet as represented in Figs. 2, 3, and 4. Thethermostat is connected to the direct current control circuit whichincludes the rectiiier bridge shown at 1| connected to secondary winding12 of transformer 13 whose primary winding 14 connects to the powersupply circuit 66. A main switch 15 is provided for cutting oil theentire cabinet electrical service from the power supply line 66 which isusually 110 volts alternating current. The transformer 73 appropriatelysteps down the power supply to the thermostatic control circuit foroperation of solenoid winding 69. Fan motor 5B normally operatescontinuously although the condition of heat within the work chamber mayvary. Such condition is controlled by the cutting on or oi of the Wirecoils 63a and 63h of the heater 63 as the thermostat 19 may determine.Selector switch 65 is manually controlled from the apparatus controlpanel exterior yof the cabinet structure for connecting the wire coils63a and 63D in parallel in order to obtain maximum temperatureconditions or connecting the wire coils 63a and 63D in series in orderto obtain lower temperature conditions or to select merely a single wirecoil and eliminate the other wire coil from the circuit in order t0obtain medium temperature conditions.

In addition to the mercury switch 61 controlled by armature 68 which isoperated by solenoid winding 69, I also provide a coacting mercuryswitch 11 having its contacts connected to selector switch 18 tothepower supply line 66 and to the blower motor 28. Selector switch 18is manually controlled from the apparatus control panel externally ofthe cabinet structure and when moved to contact 19 places the blowermoto-r under control of mercury switch 11, but when moved to contact 89eliminates the control of blower motor 28 from contacts 11 and allo-wsthe blower motor 28 to run continuously except as may be determined by;the externally manually controlled Vswitch 8| mounted on the apparatuspanel. An

alternative of this arrangement includes a provision of resistorsallowing blower motor 28 to be continuously controlled by mercury switch11 at different speeds. The manually operated switch 8l when closedplaces blower motor 28 under control of the set of contacts in mercuryswitch 11 assuming manually controlled switch 18 to be moved to contact19. So long as blower motor 28 is operating pilot lamp 82 is lightedthrough suitable power reducing resistor 83, the pilot lamp 82 andresistor 83 combination being effectively in parallel with blower motor28 and the power supply line 66. Without pilot lamp 82 operating on theapparatus control panel externally of the cabinet, the operatingcondition of blower motor 28 cannot readily be determined inasmuch asobservation into the cabinet from the exterior thereof is restricted toa relatively small observing window and the sound of the running motorwithin the cabinet is substantially muffled by the cabinet structure. Asuitable convenience outlet represented at 84 is connected in a shuntwith the power supply line 66 and mounted on the apparatus control panelexternally of the cabinet structure.

The cabinet is installed in a location away from heated radiators ordirect sun light. It is mounted on a reasonably level floor or platformand the power circuit $6 connected to a suitable power source such as110 volt 60 cycle alternating current. I iind it desirable to ground thecabinet, power service conduit system and interior of the cabinet wallas represented schematically at Il I and H2 of Fig. '1.

Dry Ice represented generally in commercial block form at l is depositedin basket 2Q, the work set up in the working compartment lli and thecabinet closed. The Dry Ice is pumped over as a gas into the workingcompartment by blower under control of the thermostat 18 and heatersystem 63. Assuming that a temperature of minus degrees F. is desired,thermostat 18 is set for this temperature and locked. Calibration can bemade by observing a thermometer inside the working chamber and checkingthe thermometer reading the instant that the pilot lamp 82 isilluminated on the control panel exterior to the cabinet which shows theinstant that the blower motor 28 is energized for the minus 50 degreesF. setting of thermostat 18.

Operation of cabinet at 40 deg. to -100 deg. F.

In order to operate the cabinet over ranges, for example, of #40 to 100F. the Dry Ice compartment 28 is filled to the top with Dry Ice crushedto approximately egg size. It is advisable not to use powdered or tooilnely pulverized ice as it reduces the surface area, and, in turn,reduces the pull-down rate. The slide damper d8 located in the workingcompartment I4 in the upper left-hand corner is pulled wide open. Thebox will now rapidly pull down in temperature at the following rates:

From room to -40 deg. F.: Approximately 20 minutes.

From room to -100 deg. F.: Approximately '10 minutes.

However, when the box reaches a temperature of -90 degrees F., it may benecessary to recharge the dry ice compartment with more Dry Ice which,in turn, increases the surface area and rapidly brings the box down to100 degrees F.

For any temperature control in the range of -40 degrees F. to 100degrees F., the slide damper 48 should be adjusted to half-openposition. Simply vset the regulator 10 for the desired temperature inthis range with the heat switch 65 in the oi" position, and it will givesatisfactory regulation.

For temperatures from 0 degrees to -40 degrees F., the slide damper 48should be in the 1A open position.

When working at or near 0 degrees F. or above, it is advisable to putthe Dry Ice in as large lumps as possible (normally 1 or 2 pieces whichwill ll compartment). This provides better control at thesetemperatures. It may also be necessary at any temperature from -20degrees on up to room temperature to turn the heater switch 65 to lowposition to oilset the refrigeration effect due to leakage through theinterior insulation.

Operation from room tempeaiture to 220 degrees F.

The same procedure is followed for setting the thermoregulatcr 18 forthese higher temperatures. Any Dry Ice that may be present in the boxshould be removed, and the heater switch 65 turned to high until desiredtemperature is reached. It will require from `3 to 4 hours for the boxto rise from room to 220 -degrees F. with the switch on high Switchpositions are as follows:

From room to degrees F.: low From 120 degrees F. to 160 degrees'F.:medium From 160 degrees F. to 220 degrees F.: high In opening the lid ofthe box at the high temperatures, it is advisable that no fan or draftof cool air be made to strike the observation glass at the underside ofthe lid as sudden change of temperature might crack the glass.

Safety thermostat In order to avoid dangerous conditions which mightresult from failure of the thermostat 10 to function, I provide a safetythermostat i I8 in the heater circuit which will open at approximately230 degrees F. preventing the box from rising any higher than this,thereby causing damage. This safety thermostat may be convenientlylocated on the lower left-hand of the heater frame 64. p

Normal Dry Ice consumption at -100 degrees F. after the initialpull--down is approximately 2 lbs. per hour. Dry Ice consumption at -40degrees F. is approximately 1.5 lbs. per hour. Dry Ice consumption at 0degrees F., with heat switch on low heat (input watts) is approximately2 lbs. per hour. Dry Ice consumption at 0 degrees F., with no heat onand Dry Ice in one large piece, is approximately 1.25 lbs. per hour.

The equipment of my invention is highly practical inasmuch as Dry Ice isnow commercially obtainable through wide distribution channels andprovides a convenient means for securing refrigeration at thetemperatures obtained in the system of my invention.

The only maintenance required with the equipment is the occasionaloiling of the fan motor 58 and blower motor 28. Replacement of the pilotlight 82 is readily made. It may be necessary to renew the heater coils63a and 63h from time to time.

The apparatus of my invention has wide application in industry such asthe shrinking of rivets for mass production riveting operations, thechilling of aluminum rivets to retard hardening and maintain them soitenough for driving; the storing of metal parts at low temperatures forconditioning the parts prior to use as in chilling the parts for`expansion fitting; the treating of tool and other steels by chilling toproduce desired characteristics otherwise difficult to obtain byordinary methods of treatment; the accelerated aging of metals to`prevent growth; the storing of serums, blood, chemicals, etc.; thetesting of aircraft equipment and materials of every description fordetermining their durability, performance, etc. at low temperatures andas a foodfreezing pilot plant. The portability of the equipment is oneof its outstanding features in addition to its low cost andsimplification of design for quantity production.

In the operation of the refrigeration apparatus of my invention the gasfrom the solidified gas compartment is accumulated in a confined aiea orcolumn inthe duct system 4 |44 which serves as a trap from which the gasdoes not run out until the blower fan 35 :is initiated in motion.

The confined column of gas is then lifted by the fan 35 and pumped`through the work compartment for maintaining the sub-zero temperaturethereon. 'This process of lifting and pumping the column of gascontinues until the predetermined thermostat controlled temperature inthe work compartment is reached.

Wherever in the specification and/or claims I may use the expression dryice I desire that this be understood to mean any solidified gas. Myinvention is not restricted to the use of CO2 as any solidied gas may beemployed for securing the sub-zero temperatures obtainable intheapparatus of my invention.

Although I vhave described my invention .in certain of its preferredembodiments, I realize that changes and modifications may be made and Iintend no limitations upon my invention other than may be imposed by thescope of the appended claims.

What I claim as new and desireto secure by Letters Patent of the UnitedStates is as follows:

1. Heating and cooling apparatus comprising a cabinet having a workcompartment and a solidified gas refrigeration compartment incommunication, a constantly driven circulator .fan in said workcompartment, a heater associated With said fan, a carrier for solidifiedgas insertable into said solidified gas refrigeration compartment, a fanin said solidified gas refrigeration compartment, a driving means forthe fan in said solidified gas refrigeration compartment forestablishing circulating currents through said solidified gascompartment and Ythrough saidwork compartment, a power supply source forsupplying power to said constantly driven circulator, andthermostatically controlled switching means for selectively connectingsaid heater and the driving means for the fan in said solidifiedgascompartment with said power supply source.

2. Heating and cooling apparatus. comprising a cabinet having a workcompartment and a solidified gas refrigeration compartment incommunication, a constantly driven circulator `fan in said workcompartment, a heater disposed adjacent said fama carrier for solidifiedgas insertable into said solidified gas refrigeration compartment, a fanin said solidified gas refrigeraton compartment, a driving means forthefan in said solidified gas refrigeration compartment for establishingcirculating currents through said `solidified gas compartment 'andthrough lsaid `work compartment, a p'cwer supply source for'sup- `plyingpower to said vconstantly driven circulator, vand thermostaticallycontrolled switchingmeans for alternately and selectively connectingsaid heater and the driving means for the fan `insaid solidified gascompartment with said power supply source.

3. Heating and cooling apparatus comprising a vcabinet having a workcompartment and a solidified gas refrigeration compartment incommunication, aconstantly driven circulator fan in said workcompartment, a heater disposed adjacent said fan, a carrier forsolidified gas insertable into said solidified gas refrigerationcompartment, a fan in said solidified gas refrigeration compartment, adriving means for the fan in said solidified gas refrigerationcompartment for establishing circulating currents through saidsolidified gas compartment and through said Work compartment, a powersupply source for supplying power to said constantly driven circulator,thermostatically controlled switching means for alternately andselectively connecting said heater and the driving means for the fan insaid solidified gas compartment with said power supply source, and meansassociated with the fan in said solidified gas refrigeration compartmentfor controlling the volumetric transfer of gas between saidcompartments.

4. Heating and cooling apparatus comprising a cabinet having a workcompartment and a solidified gas refrigeration compartment incommunication, a constantly driven circulator fan in said workcompartment, a heater disposed adjacent said fan, a carrier forsolidified gas insertable into said solidified gas compartment, adriving means for the fan in said solidified gas refrigerationcompartment for establishing circulating currents through saidsolidified gas compartments and through said work compartment, a powersupply source for supplying power to said constantly driven circulator,thermostatically controlled switching means for alternately andselectively connecting said heater and the driving means for the fan insaid solidified gas compartment with said power supply source, and avalve interposed between the fan in said solidified gas refrigerationcompartment and said work compartment for regulating the volumetrictransfer of gas between said compartments.

5. Heating and cooling apparatus comprising a cabinet having a workcompartment and a solidified gas refrigeration compartment incommunication, a constantly driven circulator fan in said workcompartment, a heater associated with said fan, a carrier for solidifiedgas insertable into said solidified gas refrigeration compartment, aduct extending between a position adjacent the base of said solidifiedgas refrigeration compartment and a position adjacent the top of saidwork compartment, a fan disposed in said duct, a motor for driving saidfan for circulating gas from said solidified gas refrigerationcompartment through said work compartment, a power supply source forsupplying power to said constantly driven circulator, andthermostatically controlled switching means for selectively connectingsaid heater and the driving means insaid solidified gas compartment withsaid power supply source.

6. Heating and cooling apparatus comprising a cabinet structureincluding a solidified gas refrigeration compartment and a workcompartment in communication, a blower in said solidified gasrefrigeration compartment for pumping gas therefrom into said workcompartment, `a motor for driving said blower, a circulator associatedwithl said work compartment, heater coils Aassociated with saidcirculator, thermostatic controlimeans associated with said workcompartment, a power supply circuit, and means controlled by saidthermostatlc control means for selectively connecting either the heatercoils or the driving motor for said blower to said power supply circuitaccording to the temperature conditions in said work compartment.

7. Heating and cooling apparatus comprising a Itemperature controlledcabinet including a, solidied gas refrigeration compartment incommunication and a work compartment, a. motor driven blower unit insaid solidied gas refrigeration compartment, a heater unit in said Workcompartment, a motor driven fan adjacent said heater unit, a powersource, a thermostat located in said 'work compartment, circuitsinterconnecting said power source and said thermostat, a two-positionrelay controlled by said thermostat, a pair of contactors controlled bysaid relay, one

10 pair of contactcrs being normally open when the other pair ofcontactors is normally closed, circuit connections between one pair ofsaid contactors and said heater unit, and circuit connections betweenthe other pair of contactors and said motor driven blower unit wherebysaid heater unit and said motor driven blower unit are selectivelyenergized from said power source according to the position of saidtwo-position relaye NATHAN MORRIS.

REFERENCES CITED UNITED STATES PATENTS Name Date Russell Oct. 10, 1944Number

